package test;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.security.Key;

/**
 * Created by Administrator on 16-4-14.
 */
public class DES {
    public static final String ALGORITHM_DES = "DES/ECB/PKCS5Padding";

    /**
     * DES算法，加密
     *
     * @param data 待加密字符串
     * @param key  加密私钥，长度不能够小于8位
     * @return 加密后的字节数组，一般结合Base64编码使用
     */
    public static byte[] encode(String key, String data) throws Exception {
        return encode(key, data.getBytes(Global.CHARSET));
    }

    /**
     * DES算法，加密
     *
     * @param data 待加密字符串
     * @param key  加密私钥，长度不能够小于8位
     * @return 加密后的字节数组，一般结合Base64编码使用
     */
    public static byte[] encode(String key, byte[] data) throws Exception {
        try {
            DESKeySpec dks = new DESKeySpec(key.getBytes(Global.CHARSET));

            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            //key的长度不能够小于8位字节
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
//            IvParameterSpec iv = new IvParameterSpec(key.getBytes());
//            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.ENCRYPT_MODE, secretKey);

            byte[] bytes = cipher.doFinal(data);
            return bytes;

        } catch (Exception e) {
            throw new Exception(e);
        }
    }

    /**
     * DES算法，解密
     *
     * @param data 待解密字符串
     * @param key  解密私钥，长度不能够小于8位
     * @return 解密后的字节数组
     * @throws Exception 异常
     */
    public static byte[] decode(String key, byte[] data) throws Exception {
        try {
            DESKeySpec dks = new DESKeySpec(key.getBytes(Global.CHARSET));
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            //key的长度不能够小于8位字节
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
//            IvParameterSpec iv = new IvParameterSpec(key.getBytes());
//            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            return cipher.doFinal(data);
        } catch (Exception e) {
            throw new Exception(e);
        }
    }

}
